Since I set up my web site, CAD Files for Woodworkers (see the link
in the Woodworker's Portal of this forum), I often get e-mail from other
woodworkers asking that question. I thought it would be appropriate for
me to set down some guidelines from my experience that might be helpful
to someone faced with that decision.

What is CAD?

Simply put, Computer Aided Design (Drafting, Drawing) software is a
computer program that allows you to use a mouse or electronic drawing
pad to draw objects to exact levels of precision. That object can be anything
from a jet engine to a bookcase. The software doesn't draw the object
for you. You still need to tell it how wide, how tall, how long, but it
makes it very easy to experiment with different dimensions, allowing you
to see the proportions of an object and determine if it is pleasing to
the eye.

The biggest advantage to CAD software is its ability to let the draftsman
edit a design. Once a drawing is completed, it is fairly easy to adjust
the height, width, etc. or try different detail treatments on a basic
object. When you change the proportions in a CAD drawing, the dimensions
are changed automatically to the new size. So a case that is 66 inches
tall can be 'shrunk' to 34 inches in a matter of seconds to create a companion
piece (see Figure 1).

Who will enjoy using CAD?

I believe people who enjoy challenging puzzles will enjoy learning how
to use a CAD program. Almost all CAD software has a rather steep learning
curve because you have to 'relearn' how to draw. It is a skill that absolutely
requires you to read the manual and figure out how it works. Successful
CAD users are people who have patience. They are also people who derive
almost as much satisfaction in designing a piece of furniture as building
it. It helps if you have a basic understanding of the principles of drafting.
Most woodworking plans created by amateurs like myself are done in the
3-view style with a 'Top', 'Front', and 'Side' view of the piece. Some
have tackled 3D (three dimensional modeling), but it is a quantum leap
from simple 2D CAD software.

Why CAD?

Much of the power in a CAD program is contained in the special drawing
tools that are available to the user. Mastering those tools takes the
frustration out of using the program. There are tools that will allow
you to lock onto the end point or mid-point of a line, the intersection
of two lines, the center point of an arc or circle, and many other points
in a drawing. It simplifies the process to be able to have the software
lock onto one of these points rather than tediously trying to position
a mouse cursor exactly on the point.

There are tools that will create a radius or chamfer between two intersecting
lines for when you're wanting to spruce up a detailed edge. You can specify
the angle you want one line to have in relationship with another and trust
that the angle drawn will be exact. You can also lock the cursor so it
will only move horizontally or vertically. That comes in handy when you
are drawing a long line that will extend off the edge of the screen. You
don't have to worry about it moving off of the horizontal or vertical
plane.

CAD programs let you zoom in on a section of a drawing without losing
any of the detail. With conventional drawing programs the lines get bigger
the tighter you zoom in the view. With CAD the lines are always the same
thickness regardless of the zoom factor (see Figure 2).

Maybe the nicest thing about drawing with CAD software is that you can
draw your piece full scale, whether it is a small jewelry box or the floor
plan for a house. You don't have to go through the mental gymnastics of
calculating scale as you draw. Just draw it full size and let the software
scale it to fit your printer page.

What software should I start with?

I encourage all first time CAD users to not purchase one of the
high end programs that professionals use. Simple 2D software will meet
the needs of most woodworkers, and it will give them a chance to see if
they enjoy using CAD without making a major monetary commitment. High
end programs sell for thousands of dollars. Medium range software still
costs several hundred, but there are some good introductory programs that
can be purchased for under $100.

DeltaCAD is another easy to learn (well... easier to learn)
package that can be downloaded from the web. Their site is at http://www.dcad.com.
You get a 45 day demo period for free, but must register it ($19.99) after
that time or lose the capability to save, edit, or print files. The manual
will cost you another $20.00, but it's still a good buy for $40 total.

There are specialized CAD programs for specific needs. Designing a house?
You can get a program that comes with all the symbols and individual items
to show walls, doors, furniture, etc. There's also one for landscaping,
with symbols for trees, shrubs, walkways, etc. There are even special
programs for designing kitchen cabinets, but again... these are fairly
expensive because of the limited size of their market.

One good source to keep an eye on is the internet auction sites such
as onsale.com and ebay.com. Both of them have new and used CAD software
for sale, and sometimes you can even find an early version of AutoCAD
for under $100. AutoCAD is pretty much the Cadillac of the industry. The
professional version sells for over $2000, but there is a version called
AutoCAD LT (lite) that can be purchased at many college bookstores for
under $200. It's a stripped down version of it's big brother, but still
a very powerful CAD program. You might want to check with an area community
college to see if they offer classes in CAD. It would be a great way to
learn the software from a professional who uses it.

Summary

So, is CAD for you? You're the only one who can answer that. Understand
that while you are learning to use the software, you will be able to draw
ten tables... or chairs... or whatever... faster than it will take
you to draw one with CAD, but after you've mastered the tools,
you'll wonder how you ever designed anything without it.